Spin-resolved photoemission

For the spin resolving photoemission and spin polarized metastable de-excitation spectroscopy measurements the films were magnetized by a current pulse through a coil close to the sample along the [110] direction of the tungsten substrate. 

Fig. 5.7 Left spin resolved photoemission spectra for thin iron films on W(llO) taken with unpolarized light (hv = 21.22 eV). Right spin integrated spectra taken with circularly polarized radiation (hv = 21.2 eV) for emission angles between 0° < 6 < 15°. The thin lines in the MCDAD spectra mark the position of the valence band maxima in normal emission. Reprinted from [26], Copyright (1998), with permission from Elsevier...

However, in contrast to the iron island stmcture on tungsten, where the existence of a complete iron monolayer was shown by STM investigations [59], it was up to now impossible to carry out any element specific analysis in between two islands. Spin resolved photoemission data of Co/W(110) [14] proof that a monolayer of cobalt at room temperature has no remnant magnetization. Therefore, the magnetic effect displayed in Fig. 5.15 cannot result from the cobalt monolayer, the magnetic phenomenon observed here is connected with the island stmcture. 

The Cr02 electronic structure was solved only in 1987 by Kamper et al. [63]. Cr02 is a half-metallic ferromagnet that is, it is a metal for the majority (spin up) electrons, but exhibits a semiconductor-type gap for the majority (spin down) electrons (Figure 19.4). This picture was confirmed by a spin-resolved photoemission from polycrystalline Cr02 films, which showed a spin polarization of almost 100% for... 

Shimada K, Mizokawa T, Mamiya K, Saitoh T, Fujimori A, Ono K, Kakizaki A, Ishii T, Shirai M, Kamimitra T (1998) Spin-integrated and spin-resolved photoemission study of Fe chalcogenides. Phys Rev B 57 8845-8853... 

In Section 3.2.2.5.1, an outline is given of how the spin polarization of the photoelectrons can be measured after their energies and emission angles have been preselected by passing through a hemispherical sector analyzer, thus enabling spin-resolved photoemission experiments (see also Chapter 7). 

Keywords Surface reconstructions surface states angular resolved photoemission scanning tunneling spectroscopy spin polarized spectroscopy self-organized nucleation. 

Sinkovic B, Tjeng LH, Brookes NB et al (1997) Local electronic and magnetic structure of Ni below and above Tc a spin-resolved circularly polarized resonant photoemission study. Phys Rev Lett 79 3510... 

Andreyev O, Koroteev YM, Snchez Albaneda M et al (2006) Spin-resolved two-photon photoemission study of the surface resonance state on Co/Cu(001). Phys Rev B 74 195416... 

The electronic structure of magnetic solids can be investigated in a very detailed way using spin- and angle-resolved photoemission. Adopting the so-called one-step model, the photocurrent at the detector is described by a 2 x 2 spin-density matrix (Braun 1996 Feder 1985),... 

SPIN RESOLVED INVERSE PHOTOEMISSION FROM LAYERED MAGNETIC NANOSTRUCTURES... 

B. Vogt, B. Schmiedeskamp, and U. Heinzmann. Spin-Resolved Core and Valence Electron Photoemission from Non-epitaxially Grown Pb Layers on Pt(lll). Vacuum 41 1118 (1990). 

Information on the spin resolved band structure of ferromagnetic materials can directly be obtained from spin resolving photoelectron spectroscopy. Using polarized radiation spin integrating photoemission techniques already enable to have access to magnetic properties. An enhancement of the surface sensitivity can be achieved using neutral excited spin polarized atoms which move towards the sample and are de-excited by tunneling electrons from the surface with a subsequent emission of electrons. 

If a spin-polarised electron gun is used then separate spectra of the unoccupied spin-up and spin-down density of states can be produced that are analogous to the spin-up and spin-down spectra of the occupied states produced by spin-resolved ultraviolet photoemission spectroscopy (SRUPS). This is also known as spin polarised inverse photoelectron spectroscopy (SPIPES). 

SRUPS Spin-Resolved Ultraviolet Photoemission Spectroscopy, 20... 

The observation of the CT gap should be contrasted with the predictions of band theory. Local-density-approximation (LDA) calculations performed for a number of undoped materials predict these systems to be metals since die Cu 3d and O 2p orbitals form a conduction band which is half-filled (for a review see Pickett 1989). The spin-polarized version of this band theory is not sufficiently accurate to yield an antiferromagnetic state of the insulating compound (Pickett et al. 1992). Thus LDA calculations fail to account for the two principal features of undoped materials the insulating gap and antiferromagnetic ordering. However, despite these serious problems these calculations do yield accurate values for the Fermi surface crossings as observed by angle-resolved photoemission (for a review see Pickett et al. 1992 see also ch. 201 of this Handbook). 

SPARPES spin-polarized angle-resolved photoemission spectroscopy... 

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